1. Field of the Invention
The present invention relates generally to a lens module, and more particularly to a projection lens.
2. Description of the Related Art
As the improvement of image technology, more and more people use projector in presentation, video conference, meeting, and video watching. In order to improve the portability of the projector, the lens, which is mounted on the projector, is asked to be as smaller and lighter as possible for a micro projector. The lens are asked to have high optical performance also except for the weight and size to project images with high image resolution and contrast. Therefore, size and optical performance are the first two important facts for the lens of micro-projector.
In order to increase optical performance, the lenses usually have a lot of lens groups therein, and some of them even have more than a dozen. On the contrary, in order to reduce size and weight, some lenses only have a few lenses, and, however, this kind of lens module couldn't provide a good optical performance.
Therefore, there still are some places that need to improve in the conventional lens for the micro projector.